Shock-absorber.



. UNITED STATES PATENT .OFFICE WILLIAM F. SERVICE, 0F .JERSEY CITY, NEW JERSEY, ASSIGNOR TO WILLIAM STERLING, OF MIFFLINBURG, 'i PENNSYLVANIA.

shocK-ABsoRBER. I

Specification of Letters Patent.

Patented Feb. 22, 1916.'

Application filed January 29, 1913. Serial No. 744,802.

To all whom z't may confiera.'

-Be 'it known that I, WILLIAM F. SnnviCE, a citizen of the United States, and a resident of Jersey City, county of Hudson, and State `of New Jersey, haveinvented certain new and useful Improvements in Shock-Albsorbers, of which the following 1s a spec1fication. t

This inventi-on relates to shock absorbers for automobiles 'of the type wherein the compressipn of air is utilized to check lthe excessive action of the springs when the vehicle encounters irregularities in the road bed.

Theprimary object of the invention is the devising of means whereby the shock that would otherwise occur from the compression of the vehicle Asprings is prevented by the compression of a volume of air, and

. whereby the shock that would otherwise follow due to the recoil of the springs is prevented by a further compression of a part of the volume of air already compressed.

7 The various other objects of the inventionV will be more fully set forth in the'following description of the invention which consists in the new and novel features of construction and combination of parts hereinafter set forth and claimed.

This invention consists of low and high pressure cylinders arranged to move in pposite directions7 and provided, each, with a piston which is operatively connected to the other cylinder to adapt the pistons to operate alternatingly on their compression strokes, and means for permitting air to pass under a predetermined pressure from the low pressure to the high pressure cylinder on the vcompression stroke of the low pressure cylinder to thereby supply agr under pressure for the compression stroke of the high pressure cylinder.

eferring to the accompanying drawings Figure 1 is a central sectional elevation ofthe shock absorber. Fig. 2 is a View l'simila/r to Fig. 1 of the upper end' of the absorler showing a modification, and Fig. 3 is a view similar to Fig. 2 showing anothr modification.y l

The low pressure cylinder of the device comprises' a cylinder"1 provided With a closed head 2 at the outer end, and a piston 3 adapted to Work in the cylinder.

The high pressure cylinder comprises the cylinder 4 secured at its inner end to the piston 3 which acts as a head therefor, the cylinder 4 at the same time serving as a. piston rod for the piston 3. The cylinder 1 is provided at its inner end with the open head 5 through which the cylinder 4 passes. A closed head 6 is secured tothe outer end of cylinder .4, and is preferably extended to serve as a?, head for the cylinder' 7 to which it is secured. Thiscylindrfis not essential but is preferably usedffs a dust shield to prevent dust from entering the cylinder 1 through the openings in its head 5. The shield is provided with perforations to permit air toenter and is of suitable length to overlap the cylinder 1.

The high pressure cylinder is provided with a piston 8 secured to la rod 9 which extends into the cylinder l through an orilice in the pistn 3 and is secured at its outer end in the head 2.V A stufling box 1Q is hee shown in the piston 3 for they piston rod 9 and an orifice. 11 is provided through the piston 3 to afford an uninterrupted com municatio'n between the active sides of the two cylinders. If desired, however, the orilice and stuffing box canbe omitted and the communication between theI two cylinders can be provided for through the opening in the piston 3 through which the rod 9 passes.

The pistons are here shown as formed of cup shaped leather; the pist-on 8 'being formed of the cup shaped disk of leather' 12 directed toward the compression side of the cylinder and supported between the collars 13 and 14, and the\piston 3 being formed of the cup shaped disk 15 directed toward the compression side of the cylinder and supported 'between the collars 1G and 17. The collars 14 and 17 form a snug slid ing fit With their respective cylinders, and are each provided with peripheral slots 18 to permit air to'pass them. The cup leather type of pistons 'are preferably used as they permit the leakage of air past them when they are atrest and also permit air to pass them to the compression end of the cylinders `when they are mpvingfrom that end. The

x piston 3 is provided with an orifice 19, in

which is arranged a ball valve-V20, seated by a spring 21 to permit air to 'pass from thecylindei` 1 to the cylinder' 4, -the spring being of. a suitable strength to permit the valve being opened only when the desired pressure has been reached in the cylinder v1. 4The'device is provided with suitable means;

' cylinder l.

as for instance, the perforated lugs 22, for securing it between the spring and chassis of the vehicle, or ptherwise in the usual manr ner.

Figs. 2 and 3 are modiications'of Fig. l in that the cylinder 4 of Fig. lis'elosed at Aits outer end, whereas in ,lf-ig. llt is provided with an opening controlled by the ball valve 23 to permit an exit of air, while` in Figf an opening isv provided which is regulated by a cock 24.

The operationot the .de vice is as follows :H'When the ruiming gear of the vehicle receives a jolt, theresult is to compress ythe springs. This 'forces the ends-2 and i3 of the device toward eachother thereby compressing the air in the low pressure This prevents the shock `that would occur from' the excessive conipression of thc springs. During this period when a predetermined pressure has been reached in the low pressui'e cylinder, the valve opens and permits .part of the com# pressed air to escape into the high pressure cylinderv 4. l/Vhen the recoil of the compressed vehicle springsbegins the tendency is to move the ends 2` and 6 of the device away from each other. This produces' a "compression of the already compressed air in the high pressure cylinder 4 and thereby 'checks the shock to the chassis that would otherwise occur. The shoclcdue to the recoil of the springs is muchl more noticeable than the shock due. to their compression. It is for this reason that the high pressure [cylinder is used to p revent this vshock and the low pressure cylinder to prevent the lesser shock due to the compression of the springs. l

Immediately upon the checking of the recoil shock, the pressure in the high pressure cylinder begins to be released by the air therein leaking 'through the orifice 11 to the low pressure cylinder, whose volume has been increasing during' the compression in -the high pressure cylinder with a corre.-

admirably adapting it for releasing the pressure in the high pressure cylinder. By thus releasing the pressure in the, high pressure cylinder, the springs are permitted to gradually assume their normal positions.

The cup shaped leather parts of the pisA tous 3 and 8 permit leakage-of air pastthem whcn they are'not compressing, thereby permitting ythe pressures irrt-he cylinders to equalize to atmosphere.; 11,-y nient of the piston B tdyv dth'ehead G compresses theair in thejouteii end of the cylmdcrfithereby as. 'sting the low pressure cylinder .lin absorbingthe shock of compression of the springs, and at the same time. permitting part of the air thus compressed to pass it and enter the inner end eliectivencss of the high pressure cylinder on the recoil of-thc springs.

. In Fig 2 the valve 23 permits the air in the outer end of the cylinder 4 tov escape :'nd therebyto a greater or extent, pre- 7o ients thc compression in that end of thc cylinder during the cmnm-essiou. in Vthe low pressure; cylimlcr.'aiid causes a partial vacuum to be formed during the compression parting from the spirit of the inventioi'l, provided the means set forth in the following claims bc employed.

I claimv l. A pneuimrtic shock absorber comprising a lou' pressurecylinder, a high'pressure cylinder telescoped in said low pressure cylinder. a piston for the low pressure cylnder between said cylinders andoperaativelv connected to the highv pressure cylindcr, and a piston for the high pressure cylinder operatively connected to the low presv sure cylinder whereby one cylinderl expands \.hile the other compresses as the'cylindersl are moved laxially 'relative'.to' eachother. said cylinders being in communicationat their inner and compression ends. 10

Q. A shock absorber comprising a low pressure cylinder, al high pressure `cylinder, a piston for the low pressure cylinder be-l tween the said cylinders and operatively l connected to the high pressure cylinder for 10fcompressing air in the outer end ofthe low pressure cylinder, and a piston for the high pressure cylinder operatively connected to the low pressure cylinder for compressing nir iu the inner en-d of the high pressure 11i l cylinder, said pistons Ibeing adaptedv to comspending decrease 1n its pressure. thereby pi-"ss alternatingly, said cylinders being in communication at their compression ends to permit air beingcompressedin the low pressure cylinder to be forced in thehigh pres-N5 sure cylinder previous to its 'compression1 stroke. l2 3. A shock absorber comprising a l'ow' pressure cylinder, a high pressure cylinder,"l a piston for the lovv pressure Cylinder' Op-v 12A" eratively connected to the high pressure cylinder for compri sing air in the Outer Aend of the low pre. ure cylinder, va piston for' the high pressure cylinder operatively-conf. ncctcd to the low pressurecylindcr for c0m- 125 pressing air in the inner end of the `high pressure cylinder, said pistons being adapt-v` y ed to connucssaltcrnatingly, and means for1V i permitting air to pass from the low preS- i sure cylinder to thehigh pressure cylin- Q Cir der when a predetermined pressure has been attained in the low pressure cylinder at the compression stroke thereof.

i. A shock absorber comprising a low pressure cylinder, a piston for the low pressure cylinder, a high pressure cylinder secured to the said piston to serve as a piston rod therefor, said piston extending between the two cylinders, a piston for the high pressure cylinder, and a piston rod for the piston of the high pressure cylinder' passing through the active end of the "high pressure cylinder operatively connected to the low pressure cylinder, cylinders being in communication at their compression ends.

5. A shock absorber comprising a 10W pressure cylinder, a piston having sliding engagement with the inner wall of the low pressure cylinder, a high pressure cylinder spaced from the low pressure cylinder and secured to the said piston to serve as a piston rod therefor, a piston for the high pressure cylinder, and a piston rod for the piston of the high through the active end of the high pressure cylinder operatively connected to the low pressure cylinder, said cylinders being in communication at their compression ends, one of said pistons being adapted to permit air to pass it when at restand when moving away from the compression end ot' its cylinder.

A shock absorber comprising a low pressure cylinder, a high pressure cylinder, a piston for the low pressure cylinder op eratively connected to the high pressure cylinder, a piston for the high pressure cylinder operatively connected to the low pressure cylinder, said cylinders having a permanent communication between their compression ends, and means for atiording additional connnunication between the Cylinders at their compression ends during the compression stroke oi the .low cmnpression piston at'ter a predetermined pressure has been reached.

i. A. shock absorber comprising a low pressure cylinder, a piston having sliding engagement with the inner wall of the low pressure cylinder, a double acting cylinder pressure cylinder passing.

spaced from the low pressure cylinder and secured to the said piston to serve as a piston rod therefor, and adapted to serve as a high pressure cylinder at one end, and a low pressure cylinder at the other end, a double acting piston for thc said double acting cylinder, a piston rod for the piston operatively connected to the low pressure cylinder and means for permitting air to pass from the low to the high pressure end of the double acting cylinder on the compressimi stroke of the. low pressure cylinder', said doubie act.- ing piston being adapted` to operate on the high pressure end alternatingly with the op eration of the low pressure cylinder and to operate on the low pressure end with the operation of the low pressure cylinder, said piston being adapted to permit air to pass it frointhe low pressure to the high pressure side on the lower compression stroke.

8. A shock absorber comprising an inner cylinderiand an outer cylinder spaced from each other, a piston movable in the Space between the said cylinders, a piston movable in the' inner cylinder, said. piston being rig idly connected to the outer cylinder, means permitting air under pressure to pass from the outer cylinder to the inner cylinder, and means for gradually equalizing the pres-l sures on opposite sides of the piston in the inner cylinder when said piston is at rest.

9. A shock absorber comprising a t\vostage air compressor and having a high pressure cylinder and a low pressure cylinder one within the other, a low pressure piston mounted on the high pressure cylinder and contacting with the inner wall ot' the low pressure cylinder, a high pressure piston mounted on the low pressure cylinder and contacting with the inner wall oi' the high pressure cylinder, and sealed on its compres-- sion stroke, said cylinders being in com` munication at their compression strokes.

This specification signed and witnessed this 6th day of December, A. D. 191

WILLIAM F. SERVICE.

Signed in the presence of- SAMUEL C. YEATON, Sana A. THORNTON 

